书院课选课权重

app/admin.py

@@ -77,6 +77,7 @@ def get_normal_fields(self, request, obj: NaturalPerson = None):
             f(_m.identity), f(_m.status),
             f(_m.wechat_receive_level),
             f(_m.accept_promote), f(_m.active_score),
+            f(_m.course_priority)
         ])
         return fields
 

app/course_utils.py

@@ -12,6 +12,9 @@
 process_time: 把datetime对象转换成人类可读的时间表示
 check_course_time_conflict: 检查当前选择的课是否与已选的课上课时间冲突
 """
+from collections import Counter, defaultdict
+from typing import Callable
+
 from app.utils_dependency import *
 from app.models import (
     User,
@@ -46,7 +49,7 @@
 
 import openpyxl
 import openpyxl.worksheet.worksheet
-from random import sample
+from numpy.random import choice
 from urllib.parse import quote
 from collections import Counter
 from datetime import datetime, timedelta
@@ -608,16 +611,13 @@ def registration_status_change(course_id: int, user: NaturalPerson,
             and course_status != Course.Status.STAGE2):
         return wrong("在非选课阶段不能选课！")
 
-    need_to_create = False
-
     if action == "select":
         if CourseParticipant.objects.filter(course_id=course_id,
                                             person=user).exists():
             participant_info = CourseParticipant.objects.get(
                 course_id=course_id, person=user)
             cur_status = participant_info.status
         else:
-            need_to_create = True
             cur_status = CourseParticipant.Status.UNSELECT
 
         if course_status == Course.Status.STAGE1:
@@ -681,15 +681,11 @@ def registration_status_change(course_id: int, user: NaturalPerson,
                     course.current_participants += 1
                     course.save()
 
-                    # 由于不同用户之间的状态不共享，这个更新应该可以不加锁
-                    if need_to_create:
-                        CourseParticipant.objects.create(course_id=course_id,
-                                                         person=user,
-                                                         status=to_status)
-                    else:
-                        CourseParticipant.objects.filter(
-                            course_id=course_id,
-                            person=user).update(status=to_status)
+                    CourseParticipant.objects.update_or_create(
+                        course_id = course_id,
+                        person = user,
+                        defaults = {"status": to_status}
+                    )
                     succeed("选课成功！", context)
     except:
         return context
@@ -816,7 +812,11 @@ def draw_lots():
             if participants_num <= 0:
                 continue
 
-            participants_id = list(participants.values_list("id", flat=True))
+            participants_info = participants.values_list("id", "person__course_priority")
+            participants_id, priority = map(list, zip(*participants_info))
+            # Turn priority into a probability distribution
+            sum_priority = sum(priority)
+            priority = [i / sum_priority for i in priority]
             capacity = course.capacity
 
             if participants_num <= capacity:
@@ -828,7 +828,7 @@ def draw_lots():
                     current_participants=participants_num)
             else:
                 # 抽签；可能实现得有一些麻烦
-                lucky_ones = sample(participants_id, capacity)
+                lucky_ones = choice(participants_id, capacity, replace=False, p=priority)
                 unlucky_ones = list(
                     set(participants_id).difference(set(lucky_ones)))
                 # 不确定是否要加悲观锁
@@ -1489,3 +1489,37 @@ def download_select_info(single_course: Course | None = None):
         file_name = f'{year}{semester}选课名单汇总-{ctime}'
     # 保存并返回
     return _excel_response(wb, file_name)
+
+
+def update_course_priority(year: int, semester: str, priority_func: Callable[[int], float]):
+    """
+    根据指定学期的学时表，计算新的书院课选课权重。
+
+    :param year: 用于查找学时表 table, 一个可能值示例为2024
+    :param semester: 用于查找学时表 table。semester的值应为'Fall'或'Spring'
+    :param priority_func: 一个函数，它接受一个int，表示过去学期学时无效的书院课门数，返回新学期选课优先级(0~1)
+    :return: None
+    """
+    if semester not in ('Fall', 'Spring'):
+        raise ValueError('semester must have value of "Fall" or "Spring"!')
+    with transaction.atomic():
+        # First, all set to 1.0
+        NaturalPerson.objects.update(course_priority=1.0)
+        # Invalid records in the given semester
+        invalid_records = CourseRecord.objects.filter(
+            year = year, invalid = True, semester = semester
+        ).values_list(
+            'person__id', flat = True
+        )
+        # Counts the number of occurrences of a person's ID in invalid list
+        invalid_counter: Counter[int] = Counter(invalid_records)
+        # a[k] is the list of id of people who have k invalid records
+        a = defaultdict(list)
+        # Length of the current continuous segment
+        for person_id in invalid_counter:
+            cnt = invalid_counter[person_id]
+            a[cnt].append(person_id)
+        for i in a:
+            # There are len(a[i]) people with i invalid records
+            p = priority_func(i)
+            NaturalPerson.objects.filter(id__in = a[i]).update(course_priority = p)

app/management/commands/update_course_priority.py

@@ -0,0 +1,21 @@
+from django.core.management.base import BaseCommand
+
+from app.course_utils import update_course_priority
+
+class Command(BaseCommand):
+    # This command should be run before new semester starts
+    help = "Updates course_priority for all NaturalPerson"
+
+    def add_arguments(self, parser):
+        parser.add_argument('year', type=int, help='year of the course records to check (required)')
+        parser.add_argument('semester', type=str, help='semester of the course records to check. Valid values are: Fall, Spring (required)')
+
+    def handle(self, *args, **options):
+        try:
+            # 修改这里的这个lambda，可以实现不同的权重策略
+            update_course_priority(options['year'], options['semester'],
+                                   lambda x: 1 - 0.05 * x)
+        except Exception as e:
+            print('Error:', e.args)
+        else:
+            print('Success!')

app/migrations/0009_courseparticipant_unique_course_selection_record.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.0.9 on 2025-01-17 20:52
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("app", "0008_pool_activity_alter_poolitem_exchange_attributes_and_more"),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name="courseparticipant",
+            constraint=models.UniqueConstraint(
+                fields=("course", "person"), name="Unique course selection record"
+            ),
+        ),
+    ]

app/migrations/0010_naturalperson_course_priority.py

@@ -0,0 +1,17 @@
+# Generated by Django 5.0.9 on 2025-01-17 21:27
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("app", "0009_courseparticipant_unique_course_selection_record"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="naturalperson",
+            name="course_priority",
+            field=models.FloatField(default=1.0, verbose_name="书院课选课权重"),
+        ),
+    ]

app/models.py

@@ -362,6 +362,7 @@ class ReceiveLevel(models.IntegerChoices):
 
     accept_promote = models.BooleanField(default=True)    # 是否接受推广消息
     active_score = models.FloatField("活跃度", default=0)  # 用户活跃度
+    course_priority = models.FloatField("书院课选课权重", default=1.0)  # 书院课预选抽签权重
 
     def __str__(self):
         return str(self.name)
@@ -1580,6 +1581,9 @@ class CourseParticipant(models.Model):
     class Meta:
         verbose_name = "4.课程报名情况"
         verbose_name_plural = verbose_name
+        constraints = [
+            models.UniqueConstraint(fields = ['course', 'person'], name='Unique course selection record')
+        ]
 
     course = models.ForeignKey(Course, on_delete=models.CASCADE,
                                related_name="participant_set")